The present invention relates generally to a multi-function loading and recovery apparatus and more particularly to an improved loading and recovery apparatus having a locking L-Arm of simple design and construction that is easy and efficient to operate in a wide variety of loading, unloading, dumping and recovery applications.
There are a variety of known pallet or container loading devices which have the ability to serve a dumping function. However, these known devices suffer a number of disadvantages because of their design and construction. Generally, the known devices have complicated arm or boom assemblies necessary to achieve their designated functions. And because of their complicated arm or boom assemblies, the known devices are higher priced, require increased maintenance, require high pressure hydraulic systems to accommodate extreme load weights and are more difficult to operate. Further, while such conventional devices may also utilize a tiltable frame, these devices require a distinct third member, such as metal hooks, to connect the arm or boom assembly to the tiltable frame, in order to lift the tiltable frame. Also, while some conventional devices have the ability to retract or extend their L-Arms, no known devices have the ability to lock a L-Arm to a tiltable frame using a spring-loaded lock connected to the tilt frame and not the L-arm, and thus allow rotation of the arm and frame structure, as one unified piece, while the L-Arm i-s in such a retracted or extended position. Thus, only containers with narrowly constrained lengths can be utilized with such devices. This device obviates the need and associated cost of a subframe.
One known device, f or example, is that disclosed in U.S. Pat. No. 3,892,323. This device functions as a container loading and unloading apparatus and also operates in a dump mode. It consists of an L-Arm which is supported by the sub-frame or vehicle chassis. The L-Arm is activated by a hydraulic ram connected to the vehicle chassis and the L-Arm. The L-Arm is sectioned such that it pivots on an intermediate point along its length and is then pivotally connected to the vehicle chassis behind the rear wheels of the vehicle. The L-Arm is also horizontally extendable through the use of a second hydraulic cam located within a sleeve of the L-Arm.
However, devices of this type have several disadvantages. First, because the L-Arm is sectioned and pivotable about two points, a more complicated mechanical configuration is required which increases maintenance and material costs. Secondly, in certain modes of operation, e.g., dumping, the L-Arm pivots at the end behind the rear wheels of the vehicle. This necessitates the use of larger hydraulic cylinders for effective operation and also increases the tipping moment of the device, which decreases the amount of load which can be lifted before the front wheels of the vehicle lift off of the ground.
Other known devices suffer from these and other disadvantages. Devices of this type are disclosed in U.S. Pat. Nos. 3,819,075, 3,878,948 and 4,175,904. All of these devices have a double pivot L-Arm which necessitates more complicated parts with decreased mechanical advantage.
Another disadvantage in prior art loading devices is the requirement that the load to be recovered or loaded must be of the same configuration as the size of the truck. The pallet to be loaded is of a custom size to fit the particular truck. This requirement is a severe limitation on the use of the loading device when the precise sized pallet or load is not available. Therefore, it is also desirable to have a loading or recovery device that may accommodate a wide range of loads and pallets and still be able to operate in full tilt dumping mode or in a pallet recovery mode which may be referred to as lift and pull.